Download registration forms in test_mode so we can style them.

Also change the attendease_themes to use the liquid tag {% attendease_content %}.

We can now use the registration theme to test the registration pages.
Generate pages for schedule, session, presenters and presenter.

Relates to: https://github.com/coverall/Attendease/pull/2001
Merge branch 'master' of github.com:attendease/jekyll-attendease

Conflicts:
	README.md